A new research suggests that the reason SARS-CoV-2 manifests so differently in different people may have to do with a person’s diet, and a new six-country study involving people working on the front lines of COVID-19 care provides some interesting new evidence.
Namely, plant-based and/or fish (pescatarian) diets may help lower the odds of developing moderate to severe COVID-19 infection, according to the findings of a six-country study, published in the online journal BMJ Nutrition Prevention & Health.
In fact, the findings indicate that the two above-mentioned diets were associated with 73% and 59% lower odds, respectively, of severe disease.
The researchers surveyed 2,884 doctors and nurses whose work with patients exposed them to SARS-CoV-2. The participants were from the United States, the United Kingdom, Spain, Italy, France, and Germany. The participants were all part of a global network of healthcare professionals registered with the Survey Healthcare Globus network for healthcare market research. The researchers used this network to identify clinicians at high risk of COVID-19 infection as a result of their jobs. The survey was designed to reveal the association between self-reported diets and COVID-19 infection, severity, and duration of symptoms.
After factoring in several potentially influential variables, including age, ethnicity, medical specialty, body mass index, and lifestyle (smoking, physical activity), respondents who said they consumed plant-based diets or plant-based/pescatarian diets had, respectively, 73% and 59% lower odds of moderate to severe COVID-19 infection, compared with those who didn’t have these dietary patterns.
Expert reaction to the study
According to Science Media Centre, reaction to the research has been somewhat skeptical. Prof Gunter Kuhnle, Professor of Nutrition and Food Science at the University of Reading, stated inter alia that: “The findings of the study are not surprising: people who follow a mainly plant-based diet or eat fish are often healthier when compared to a control group with a “normal” diet. However, these results are often misleading: a plant-based or pescatarian diet is often followed by people who have an overall “healthier” lifestyle, are more physically active, better educated and belong to higher socio-economic groups – factors that are associated with better health and also a reduced risk for COVID-19 (in the UK, deprivation and social class were strongly associated with COVID-19 risk). It is therefore impossible to infer from the data in this study whether plant based or pescatarian diets offer any protection, especially as the data presented show a lot of uncertainty.”
Dr Carmen Piernas, University Research Lecturer and nutrition scientist at the Nuffield Department of Primary Care Health Sciences of the University of Oxford, suggested that conclusions need to be drawn cautiously. “The research question is interesting, but the conclusion needs to be drawn cautiously in the context of several major methodological issues.”
“Overall, this is methodologically weak and while it raises an interesting possibility that the severity of COVID-19 may be related to diet quality, a larger-scale population based study is needed to support these preliminary findings since the population studied here is unlikely to represent behaviours of the general population.”
Finally, Prof Kevin McConway, Emeritus Professor of Applied Statistics at The Open University agreed that although the findings of the study are not easy to interpret, “One possible explanation for them is the main one that the researchers give, that eating certain diets might possibly protect against severe Covid-19. The trouble is that there are several
other possible explanations that are also compatible with the findings,” while adding that “All that the authors suggest, as action, is to carry out more detailed studies on possible associations between what people eat and Covid-19 severity. That might indeed be worthwhile –though I do ask myself whether this new study was really needed to show that the more detailed studies could be worth doing. Because of these issues, it’s not at all clear from this study that anyone should contemplate changing their diet just to give protection from serious Covid-19 – maybe it would help, maybe it wouldn’t, the study just can’t tell us.”